Topic: 390 intake manifold changeover date from C6Ae-9425-G to C7AE-9425-E survey

[67gt390fb]

   There has been a lot of confusion about the changeover date from the C6AE-9425-G to the C7AE-9425-E  390 intake manifold.

    The changeover happened sometime during late 1966 and early 1967.

   If you have a 390 that rolled out in that time period , can you check the intake manifold number & casting date and the car manufacture date and post here. thanks

[J_Speegle]

Are there any other design features that are different between the two versions?

In many or most of the pictures I have its difficult to see details such as cast date or engineering number but if something like the thermostat neck was shaped differently or there was an additional cast in boss for attaching or mounting something I might be able to provide some data points with maybe things like version and car build date. Just trying to help 

[Bob Gaines]

Are there any other design features that are different between the two versions?

In many or most of the pictures I have its difficult to see details such as cast date or engineering number but if something like the thermostat neck was shaped differently or there was an additional cast in boss for attaching or mounting something I might be able to provide some data points with maybe things like version and car build date. Just trying to help 

Large thermostat and small thermostat is at least one of the differences. That difference necessitated the different looking C7AE-A one year only thermostat housing.

[J_Speegle]

Thanks but was sort of looking fro some physical difference one could see once installed and in place (the intake) since my pictures often don't have close up detailed pictures of the front of the intake with the info he's looking for. Maybe there is no difference in the runners or location of any exterior detail

[Bob Gaines]

Thanks but was sort of looking fro some physical difference one could see once installed and in place (the intake) since my pictures often don't have close up detailed pictures of the front of the intake with the info he's looking for. Maybe there is no difference in the runners or location of any exterior detail

There is a big physical difference one can see on the intake installed in place between the thermostat housings on the two intakes. The C7AE-A small thermostat housing that is used on the C7AE-E intake is physically different in appearance compared to the C5AE large thermostat housing used on the C6AE-G intake. Once you compare the differences between the two housings it should be a easy tell.   

[67gt390fb]

I will give my own observation regarding my car, for what it is worth.

C6AE-9425-G intake, casting date 6L15 in car made on 6M15

I do not have original engine.  After keeping my eye out for YEARS for a matching date C7AE intake, I grabbed the c6ae intake which at least had a "matching"  date

[jwc66k]

Here's a list of all Ford intake manifolds from "Mustang Tek" "for reference".
https://www.mustangtek.com/FordIntake.html
It may help.
Jim

[Bob Gaines]

The C7 intake uses the very hard to find and expensive C7AE-A thermostat housing which because it was only used that one year through attrition has become hard to find. They were used on 67 427 Fairlane's and 67 GT500's so consequently they get scooped up by many restoring those cars. For example if you come across any under 300.00 it's a deal. The market value right now is much higher. 

[J_Speegle]

The C7 intake uses the very hard to find and expensive C7AE-A thermostat housing which because it was only used that one year through attrition has become hard to find. They were used on 67 427 Fairlane's and 67 GT500's so consequently they get scooped up by many restoring those cars. For example if you come across any under 300.00 it's a deal. The market value right now is much higher.

That's (the thermostat housing) part of the problem with identification as it appears a fair number of examples have had that item swapped for later versions for one reason or another. Given the angle can't make out the depression either at the driver side bottom area of the housing either.

From MustangTeks pictures can't tel for sure if the carb flange only has the mid point cutouts on the C6 version or if its on both. Just looking to try and find the easy way to tell the difference if there is one.

[Bob Gaines]

That's (the thermostat housing) part of the problem with identification as it appears a fair number of examples have had that item swapped for later versions for one reason or another. Given the angle can't make out the depression either at the driver side bottom area of the housing either.

From MustangTeks pictures can't tel for sure if the carb flange only has the mid point cutouts on the C6 version or if its on both. Just looking to try and find the easy way to tell the difference if there is one.

Most of the time in my experience it is the other way around. The large thermostat earlier C5AE thermostat housing are a dime a dozen. You see them used on everything as a replacement because they are so common. It is the hard to find the small thermostat later one year only C7AE housing so that when you find it on something helps validate that it hasn't been messed with. Of course I am referring to pictures of intakes that are in a somewhat undisturbed context. On a restored car nothing's for certain.   

[67gt390fb]

there is very little difference in the appearance of the C6AE and the C7AE intakes, and only small outer size difference looking at the thermostat housings (C5AE & C7AE).

 

[Bob Gaines]

there is very little difference in the appearance of the C6AE and the C7AE intakes, and only small outer size difference looking at the thermostat housings (C5AE & C7AE).

Small difference to some may be a larger difference to those that have compared them for a long time .   For example given the correct angle for full view I can tell the difference between the C5 and C7 thermostat housings on a engine from 20 feet away. That is probably because I have been comparing them for close to 40 years which was when I became aware of the differences . The rarity of one over the other and because of supply and demand dramatic difference in used market value to the collector crowd is a huge incentive to be aware of the differences too.

[krelboyne]

My feeling is that the 'engine' assembly date is more important than the car manufactured date. The car manufactured date stamped on the door tag is the 'scheduled for build date'. Not always accurate.

There were 3 factories that built Mustangs in 1967. No way they all had a clear changeover date.

One would also need to differentiate between Automatic (Tag code 319) and Standard transmissions (Tag code 322) with that S code engine.